Low tension core adapter



y 1967 R. w. YOUNG 3,322,361

LOW TENSION CORE ADAPTER Filed Sept.' 13, 1965 2 Sheets-Sheet 1 FIG.5

INVENTOR ROGER W. YOUNG ATTORNEY May 30, 1967 R. w. YOUNG LOW TENSIONCORE ADAPTER 2 Sheets-$heet 2 Filed Sept. 3, 1965 INVENTOR ROGE R W. YOUNG ATTORNEY narrow width, very thin films having a low United StatesPatent Oiifice 3,322,361 Patented May 30, 1967 3,322,361 LOW TENSIGNCURE ADAPTER Roger W. Young, Upper Montclair, NJ, assignor to JohnDnsenhery Company, Inc, (Clifton, N.J., a corporation of New JerseyFitted Sept. 3, 1965, Ser. No. 484,865 9 Claims. (Cl. 242-669) Thisinvention relates to core adapters for use on web slitting and rewindingmachines and more particularly to core adapters of novel constructionfor use in rewinding tensile strength. In slitting and rewindingmachines, a relatively wide web of material, such as a plastic film, isslit into narrow strips, which strips are then rewound into roll form onindividual cores mounted on a pOWer driven shaft, or mandrel. In orderto provide a smooth rewinding of the cut strips, a certain amount oftension must be maintained on each individual strip during the entirerewinding operation. This is accomplished by rotating the mandrel at ahigher speed than the cores, such arrangement being commonly referred toin this art as differential winding. As the diameter of the rewoundrolls increases, the rotation of the cores decreases, since the stripsare fed to the cores by a pull roll rotating at a constant speed.Accordingly, arrangements are provided to afford slippage between thecores and the supporting mandrel, which slippage increases automaticallyas the diameter of the rewound rolls increases.

A variable factor which effects the rewinding of the cut strips is thenormal variation in gauge, or thickness of the particular material. Suchvariation results in the diameter of some rewound rolls increasing at afaster rate than others which often results in rewound rolls of inferiorquality. To overcome this problem, it is the practice to provide anarrangement wherein each core can slip, relative to the mandrel, incorrespondence with the tension of the associated strip andindependently of the other cores. This is done by inserting core spacerrings over the mandrel and between each of the rewind cores. These corespacer rings are individually keyed to the mandrel and the assembly ofspacers and cores is clamped, axially, by suitable loading means carriedby the mandrel. Thus, the core spacers, are positively driven by themandrel while each core is free to slip as the tension of the associatestrip exceeds the frictional restraining force exerted against oppositeends of the core by the spacers.

Normally, a winding machine is provided with two spaced rewind mandrels,each mandrel carrying a plurality of alternately-disposed cores andspacer rings. Adjacently-disposed strips of the slit web are directed todifferent mandrels so that the spacing of the cores on each mandrel isequal to the width of the strips. Such spacing is maintained by the corespacers.

The cores upon which the slit strips of material are wound generally areformed of a plurality of convolutions of paper wound into a rigid tube,the inside diameter of which has a commercial tolerance of inch, orgreater. Consequently, when the cores are mounted directly on themandrel and axially clamped by intervening core spacers, there is noassurance each core will rotate concentrically with the shaft axis. Suchnon-concentric rotation of the core results in wound rolls of nonuniformtension, or density. In order to provide concentric rotation of all ofthe cores, it is the practice to mount the individual cores on themandrel by means of core adapters, which adapters are in frictionalengagement with the spacer rings.

In the case of very thin film, slit into narrow strips, the amount oftension which can be applied to the strips, during the windingoperation, cannot exceed a relatively low, maximum value, otherwise thestrip may be stretched and/or torn, particularly when the machinedesirably is operated at high speeds. For operation with such films, thecore adapters must be capable of maintaining a uniform low tension onthe strips from the beginning to the end of the winding cycle, whichtension is not subject to i sudden variations arising from frictionalchanges between the adapters and spacers. Also, the adapters must beconstructed and arranged to receive cores having inside diameters whichvary within commercial limits and to rotate such cores concentricallywith the mandrel axis. Yet, the cores must readily be mounted on andremoved from the adapters. Core adapters made in accordance with thisinvention meet all of these requirements.

An object of this invention is the provision of improved core adaptersfor supporting tubular cores on a mandrel, which adapters areparticularly useful for the winding of narrow strips of very thin filminto roll form.

An object of this invention is the provision of adapters for supportingcores on a mandrel for the purpose of winding strips of material on thecores, which adapters include means for retaining the cores concentricwith the mandrel axis and means for maintaining relatively low, uniformtension on the material strips during the winding operation.

An object of this invention is the provision of an adapter forsupporting a tubular core on a mandrel, which adapter comprisesconcentrically-disposed, spaced cylindrical members, bearing meansdisposed between the said members to afford concentric rotation of themembers, and means for removably securing a core on one of the saidmembers.

An object of this invention is the provision of a core adaptercomprising concentric inner and outer cylindrical members, bearing meansdisposed between the said members, a reduced diameter portion formed onthe outer cylindrical member and adapted for insertion into an end of atubular core, and means carried by said reduceddiameter portion forpreventing relative rotation between the core and the outer cylindricalmember.

These and other objects and advantages of the invention will becomeapparent from the following description when taken with the accompanyingdrawings. It will be understood, however, that the drawings are forpurposes of illustration and are not to be construed as defining thescope or limits of the invention, reference being had for the latterpurpose to the claims appended hereto.

In the drawings wherein like reference characters denote like parts inthe several views:

FIGURE 1 is a front elevational view of a core adapter made inaccordance with one embodiment of this invention;

FIGURE 2 is a rear elevational view thereof;

FIGURE 3 is a central cross-sectional view taken along the line 3-3 ofFIGURE 1;

FIGURE 4 is a front elevational view of a core adapter made inaccordance with another embodiment of this invention;

FIGURE 5 is a central, cross-sectional view taken along the line 55 ofFIGURE 4; and

FIGURE 6 is a fragmentary front elevational view showing the coreadapters carrying cores and mounted on the mandrel of a rewindingmachine, with portions drawn in cross-section.

Referring now to FIGURES 1-3, the core adapter 10 comprises a firstouter cylindrical member 11 preferably made of aluminum and providedwith an integral, reduced-diameter portion 12, which portion has aninner circular bore formed in the free end for receiving the outer raceof a low friction bearing 13. The member 11 has a central hole 14extending therethrough, which hole has a diameter slightly larger thanthat of the winding machine mandrel for which the adapter is designed.The

outer surface of the cylindrical member 11 is provided with a relativelyshallow bore within which a smooth metal plate 15 is positioned, saidplate havmg a central hole aligned with the mandrel hole 14. Rotation ofthe plate 15, relative to the cylindrical member 11, is prevented bytwo, axially-extending pins 16 which are driven into holes formed in themember 11 and extend through diametrically-opposed holes 17 formed inthe plate.

A second outer cylindrical member 1?, made of aluminum, has an outsidediameter corresponding to that of the cylindrical member 11, said member18 being provided with an integral, reduced-diameter portion 19 having acircumferential groove 20 formed therein. The inner end of the member 18is provided with two circular bores, one such bore receiving thereduced-diameter portion 12 of the outer cylindrical member 11 and theother such bore receiving the outer race of the bearing 13.

The two cylindrical members 11 and 18 are secured together by thefastening screws 21, which screws pass through clearance holes formed inthe member 11 and are threaded into holes formed in the member 18. Inaddition to conventional lock washers, flat washers 22 are associatedwith each of the fastening screws, said flat Washers having portionsextending over the underlying plate 15. After the fastening screws arefirmly threaded into position, the two cylindrical members 11 and 1&3constitute a unitary structure which is secured to the outer race of thebearing 13.

The inner race of the ball bearing 13 is force-fitted over a tubularmember 25, made of a material having a low coefficient of friction suchas, for example, Teflon, having an inside diameter corresponding to thatof the central hole 14 formed in the cylindrical member 11. It will nowbe apparent, that bearing 13 affords relative rotation between the innertubular member 25 and the outer cylindrical structure consisting of themembers 11 and 18.

The reduced-diameter portion 19, of the cylindrical member 18, isadapted for insertion into an end of a tubular core. When the core is somounted on the adapter, it is important that the core be restrainedagainst rotation relative to the outer cylindrical structure of theadapter. For this purpose, a resilient O-ring as, made of rubber orother suitable material, is positioned in the bottom of the groove 20and supports a closely-coiled garter spring 27. It will be noted thatthe encircling garter spring extends above the groove. As mentionedabove, the tubular cores are made of paper and have diiferent insidediameters due to manufacturing tolerances. Thus, the outer peripheralsurface of the garter spring is arranged to be somewhat larger than themaximum inside diameter of the commercially available cores of given,nominal size, while the diameter of the reduced-diameter portion 19, ofthe adapter, over which the cores are to be fitted, is somewhat lessthan the minimum diameter of such cores. When the end of the core ispressed onto the adapter and over the garter spring, the resilientO-ring compresses to accommodate the particular core. Under the combinedforce developed by the spring and the O-ring, there is exerted againstthe core a radial pressure, which pressure causes the springconvolutions to bite into the inner wall of the core, slightly, therebypreventing rotation between the mounted core and the outer cyclindricalstructure of the adapter.

Reference now is made to FIGURES 4 and 5, which show a core adapter 30of modified construction, FIG- URE 4 being a front elevational view andFIGURE being a central cross-sectional view taken along the line 55 ofFIGURE 4. The outer cylindrical member 31, preferably made of aluminum,includes a reduced-diameter portion 32 having the same diameter as thereduceddiameter portion 19 of the adapter shown in FIGURES 1-3. AnO-ring 26 and a garter spring 27' are disposed within thecircumferential groove formed in the portion 32. The inner wall of themember 31 is provided with a bore receiving the outer race of thebearing 13', which bearing is retained in place by a conventional, splitretaining ring 33. An inner, tubular member 35 is secured to the innerrace of the bearing, such member corresponding to the member 25 (seeFIGURE 3), and having an inside diameter slightly larger than that ofthe mandrel. The member 35 also is made of a material having a lowcoefficient of friction. It will be clear that the bearing 13 affordsrotation of the outer and inner members 31 and 35, respectively.

The assembly of a plurality of core adapters in operative position on amandrel of a rewinding machine is shown in FIGURE 6, to which referencenow is made. The mandrel 37 has a stop collar 38 inserted thereon andsecured in place as by a set screw 39, which collar serves to positionthe adapters and cores in alignment with the incoming strips of materialto be wound into roll form. The mandrel is loaded, alternately, withspacer rings 41 and pairs of core adapters 10 and 30, each pair of coreadapters carrying a core 41. These spacer rings are made of a materialhaving a low coefiicient of friction and good compressive rigidity suchas, for example, low friction nylon. As shown in the cross-sectionalportion of FIG- URE 6, the reduced-diameter portions of the outercylindrical members of the adapters 10 and 30 are inserted into oppositeends of the core 41. Such core is rotatable with the outer cylindricalmembers of the adapters but is restrained against rotation relative tosuch members by the garter springs 27 and 27'. After the last coreassembly has been loaded on the mandrel, a last spacer ring 4t} isinserted, followed by a thrust bearing assembly 42. The loaded mandrelnow is installed on the machine.

Assuming, now, that ends of the strip material have been fastened to thecores, as by means of adhesive tape, a desired strip tension is obtainedby means of a pistontype cylinder 45 which is secured in fixed positionon the machine frame. By regulating the fluid pressure to this cylinder,a range of axial pressures can be applied to the thrust bearing 42through the piston 46 and the lever 47, said lever being pivotallycarried by the machine frame and having a bifurcated end spanning themandrel 37.

It is here pointed out that the thrust bearing 42, the spacer rings 4-!)and the core adapter assemblies are free to slide axially along themandrel. However, the spacer rings have secured theretoinwardly-extending metal keys slidably disposed within a keyway 418formed in the mandrel. Consequently, the spacer rings rotate, at alltimes, at the same speed as the mandrel, which speed is such that thesurface velocity of the core is somewhat greater than the linear speedat which the strips of material are fed to the rewind station. Since thestrips of material are fed to the cores over a pull roll, not shown,rotating at a constant speed, a certain amount of slippage must takeplace between the core and the mandrel.

In prior core adapters, each of the circular members (which are insertedinto opposite ends of the core) carries a central bushing made of a lowfriction material, which bushing has an inside diameter such that theadapter is slidably insertable on the mandrel. Thus, in operation, thereare four friction surfaces which effect the tension of the strip ofmaterial being wound on the core, namely, the areas of contact betweenthe mandrel and the two bushings and the areas of contact between eachof the circular members and the adjacent spacer ring. As the downwardweight of the wound roll increases, there is a corresponding increase inthe frictional torque between the two bushings and the mandrel. Further,the axial pressure between the spacer rings and the circular members, ofthe core adapters, decreases in effect in a long stack of core adaptersand spacer rings, due to the longitudinal, frictional resistance of theweighted cores and the torsional force of the keys, of the spacer rings,against the side wall of the mandrel keyway. These two factors militateagainst the maintenance of a relatively low, uniform tension on thestrips of material being wound.

In core adapters made in accordance with this invention, it will benoted that the spacer rings each have one end in contact with the innertubular member 35, of the adapter 30, and the other end in contact Withthe plate 15, of the adapter 10. Although there is an axial pressureapplied between the spacer ring and the tubular member 35, no slippageoccurs between these members as the ball bearing will rotate before suchslippage can take place. Also, the rewound roll is carried by thebearing with but a negligible increase in radial friction as the weightof the roll increases to its maximum value. Thus, it will be apparentthat there is only one friction surface for developing torque, namely,the area of contact between the plate and the engaged end of theproximate spacer ring. Therefore, in order to obtain the same windingtension, the axial pressure applied to the assembly of core adapters andspacer rings will be twice that required in the case of core adapters ofprior construction. The axial pressure is attenuated, in a long stack ofcore adapters and spacer rings, and the attenuation effect is a functionof :the torque and roll weight. Thus, it can be seen that by doublingthe axial pressure, the percentage attenuation error is reduced by 50%,while maintaining the same torque output. This feature is of importancewhen winding narrow strips of very thin material, wherein it isessential to maintain a relatively low, uniform strip tension throughoutthe winding cycle.

Having now described the invention, those skilled in this art will beable to make various changes and modifications without thereby departingfrom the spirit and scope of the invention as recited in the followingclaims.

I claim:

1. An adapter for use in supporting a tubular core on a mandrel, whichadapter comprises,

(a) a cylindrical outer member having a portion insertable into an endof the core,

(b) holding means carried by said outer member, said holding meanscooperating with the core to prevent relative rotation between the coreand said member,

(c) a tubular inner member concentric with said outer member andinsertable over the mandrel, and

(d) bearing means positioned between the said outer and inner members toafford relative rotation therebetween.

2. The invention as recited in claim 1, wherein the said holding meanscomprises means forming a peripheral groove in the said portion of theouter member, a resilient ring member groove, and a coiled springpositioned in said groove and over the said ring member, said springhaving convolutions normally extending radially outward of the groove.

3. The invention as recited in claim 1, wherein the said outer memberincludes a base portion provided with a central opening correspondingsubstantially to the inside diameter of the said inner member, andincluding a flat plate secured to the said base portion, said plateprovided with a central opening corresponding to the central opening inthe said base portion.

4. The invention as recited in claim 1, wherein the said inner member ismade of a material having a low coefficient of friction.

5. The invention as recited in claim 1, wherein the said bearing meanscomprises a ball bearing having inner and outer races, the inner racebeing secured to the said inner member and the outer race being securedto the said outer member.

6. An adapter for use in supporting a tubular core on a mandrelcomprising,

disposed in the bottom of the. 50

(a) a tubular inner member made of a material having a low coefficientof friction and having an inside diameter such that it is slidablyinsertable over the mandrel,

5 (b) a cylindrical outer member having a reduced-diameter portion forinsertion into an end of the core and a base portion provided with acentral opening corresponding to the inside diameter of the said innermember,

(c) a ball bearing having an inner race secured to the outer wall of thesaid inner member and an outer race secured to the inner Wall of thesaid outer member,

(d) a flat plate secured to the surface of the base portion of the saidouter member, said plate provided with a central opening correspondingto the inside diameter of the said inner member,

(e) means forming a peripheral groove in the reduceddiameter portion ofthe said outer member,

(f) a resilient ring disposed in the bottom of said groove, and

jg) a coil spring disposed in said groove and over the said ring, saidspring having convolutions normally extending radially outward of thegroove.

7. An arrangement for winding a strip of material on a core which isfrictionally driven by a mandrel, which arrangement comprises,

(a) a first adapter mounted on the mandrel and comprising concentricinner and outer members mechanically coupled to a ball bearing,

(b) a second adapter mounted on the mandrel and comprising concentricinner and outer members mechanically coupled to a ball bearing,

(c) a core carried by the outer members of both said adapters,

(d) holding means on each of the outer members of the adapters, saidholding means preventing rotation of the core relative to the said outermembers,

(e) a pair of spacer rings mounted on the mandrel 4 for positiverotation therewith, one spacer ring having an end in frictionalengagement with the outer member of the said first adapter and the otherspacer ring having an end in frictional engagement with the inner memberof the said second adapter, and

(f) means applying an axial rings.

8. The invention as recited in claim 7 including a flat plate secured toan end of the outer member of the said first adapter, and wherein theend of the said one spacer ring is in frictional engagement with thesaid plate.

9. The invention as recited in claim 8, wherein the said holding meanscomprises complementary reduceddiameter portions formed on the outermembers of both adapters, a peripheral groove formed in each suchreduced-diameter portion, resilient ring members individually disposedin the bottom of each groove, and a pair of circular coiled springsindividually positioned over the ring members and projecting radiallyoutwardly of the grooves, the arrangement being such that the springsbite into the wall of the core.

pressure to the spacer References Cited UNITED STATES PATENTS 1,955,9174/1934 Jung 2,833,488 5/1958 Kerber FRANK I. COHEN, Primary Examiner. 70N. L. MINTZ, Assistant Examiner.

1. AN ADAPTER FOR USE IN SUPPORTING A TUBULAR CORE ON A MANDREL, WHICHADAPTER COMPRISES, (A) A CYLINDRICAL OUTER MEMBER HAVING A PORTIONINSERTABLE INTO AN END OF THE CORE, (B) HOLDING MEANS CARRIED BY SAIDOUTER MEMBER, SAID HOLDING MEANS COOPERATING WITH THE CORE TO PREVENTRELATIVE ROTATION BETWEEN THE CORE AND SAID MEMBER, (C) A TUBULAR INNERMEMBER CONCENTRIC WITH SAID OUTER MEMBER AND INSERTABLE OVER THEMANDREL, AND (D) BEARING MEANS POSITIONED BETWEEN THE SAID OUTER ANDINNER MEMBERS TO AFFORD RELATIVE ROTATION THEREBETWEEN.